Learn › C9 Chord on Piano (C Dominant 9th)
New Released in April 2026
C9 Chord on Piano (C Dominant 9th)
To play the C9 chord on the piano, press C, E, G, Bb and D. It is the dominant seventh C7 plus the 9th, D. In one phrase: full and bluesy-bright, tension that still sounds smooth.
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- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
C9 and Em7b5
Above the root C sit four notes that form Em7b5: E G Bb D. A pianist can play C with the left hand and Em7b5 with the right, and the result is C9.
How C9 is built
Every chord is a recipe of scale steps. For C9 the recipe is 1 3 5 b7 9, counted from C.
Start chord: C7
| Note | Step | Interval | Keys from C |
|---|---|---|---|
| C | 1 | root | 0 |
| E | 3 | major 3rd | 4 |
| G | 5 | perfect 5th | 7 |
| Bb | b7 | minor 7th | 10 |
| D | 9 | major 9th | 14 |
Ways to place C9 on the keys
Same notes, different order. Pick the position closest to the chord you just played.
Both hands: C Bb E G D
Rootless, 3rd on the bottom: E G Bb D
Rootless, 7th on the bottom: Bb D E G
Left hand alone: C Bb
Fingering
| Left hand | C Bb | 5 1 |
|---|---|---|
| Right hand | E G D | 1 2 4 |
Practise C9 in four steps
- Say the notes out loud while you press them: C, E, G, Bb and D.
- Play C7, then C9, then C7 again, and hear what the 9th adds to the seventh.
- Try C9 in a rootless shape with the 3rd on the bottom, the position that sits closest to your last chord.
- Last, meet C9 mixed with chords you already know, in an order you did not plan.
Five minutes a day is enough to make C9 feel easy.
Keys and moves for C9
- C9 is the V chord of F major: it pulls home to F.
- Many pianists play C9 whenever C7 appears, because the 9th makes the same pull sound richer.
Play C9 in a game
Chord symbols arrive one after another and the game checks every note you play, with MIDI or the microphone. Dominant 9ths appear in the later boss challenges, next to major and minor 9ths.
Play the demoCommon questions
What is C9 on the piano?
C9 is the C dominant 9th chord: C, E, G, Bb and D, the dominant seventh C7 plus the 9th, D.
What is the difference between C9 and C7?
C7 is C E G Bb. To get C9, add D above the seventh.
Where is C9 used?
C9 is the V chord of F major: it pulls home to F. Many pianists play C9 whenever C7 appears, because the 9th makes the same pull sound richer.
Can I practise C9 with a MIDI keyboard or a real piano?
Yes. In ChordRunner a USB MIDI keyboard is detected automatically, and an acoustic or digital piano works through the microphone. The game checks that C, E, G, Bb and D sound together.
Your instrument is the controller.
ChordRunner is a browser game that teaches piano and guitar chords: a chord appears on screen, you play it on a real instrument, and your runner jumps. MIDI keyboard or microphone, both work.
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